The criminal case on negligence charges was opened after a 16-year-old student in a high school in the central Russian town of Yelets, 350 kilometers (220 miles) southeast of Moscow, collapsed and died after being forced to run more than 3 kilometers (1.86 miles) as part of a military exercise, said Yelena Namokonova, spokeswoman for the regional prosecutors office.

The boy was not identified.

Namokonova declined to say who was charged in the case, saying only that it was opened "to establish the details."

Military officials were quick to say they were not responsible. An unidentified official in the Defense Ministry told the ITAR-Tass news agency that the drills had been organized by local authorities without the participation of military officers.

Russian high schools routinely conduct military drills to prepare students for future military training, which is compulsory in Russia. But rights groups insist such exercises can be conducted only after students have undergone medical examinations.

Last year, an army officer was found responsible for the death of a high school student in Siberia during a similar drill. Prosecutors said the student was wearing a gas mask during the run, which the officer refused to let him remove. The student then became nauseous, eventually vomiting in his mask and choking to death. The officer received a suspended four-year sentence.